Cant find servlet

Hi! My question is kinda dumb. I'm used to map my servlet and it works pretty fine but if I only use applicationFolder/servlet/SampleServlet it does'nt work. I'm pretty sure that the Servlet Container can find the servlet if its under WEB-INF/classes without having to put it in the classpath because the it automatically searches the WEB-INF/classes folder. Any ideas why its not working? Anyway I'm using Tomcat and the classes are not in a package. Thanks.